Cobalt-tungsten-iron alloy



' quenched alloys at temperatures between 500 and Patented" Aug. 20, 1935 PATENT OFFICE OOBALT-TUNGSTENIRON ALLOY Werner Roster, Dortmund, Germany. alsignor to Vereinigte Stahlwerke Aktiengesellschait, Dusseldori, Germany ,No Drawing. Application 1mm 28, 1932,

Serial No. 589,585. In Germany February 18,

2 Claims. (01. 148-18) This invention relates to a process ot-treating cobalt-tungsten-iron alloys and to alloys thus treated.

Exhaustive experiments have demonstrated that alloys containing about 40 to 85% of cobalt, about 5 to 40% of tungstenand the balance substantially iron, it they contain carbon in amounts not exceeding 0.3% are very well adapted to be precipitation hardened by a special heat treatment, namely by heating the cast or rolled alloys to a temperature between about 1000 C. and the melting point of the alloy, followed by. quenching in'the air, water or oil, and then-heating the 900 G. By this treatment, the mechanical prop erties of the alloys are very considerably improved by comparison with what they were prior to the heat treatment and particularly good hardness values ensue, if the alloys contain iron in ad dition to cobalt and tungsten in the proportions mentioned. A further improvement in the quality of the alloys occurs on the tungsten content being increased to above 10%. Moreover, the alloys may contain up to 15% of other additions such as molybdenum, manganese, nickel, copper, aluminium, vanadium or titanium, without atiecting the scope of the invention such small additions are comprised by the term in the claims:

' the balance consistingsubstantially or iron".

The following examples serve to illustrate more clearly the nature of the present invention:-

1. An alloy containing 41% of cobalt, 22% of tungsten, of iron, 1.5% of vanadium and 0.08% of carbon gave; after quenching from 1300" (2., a hardness of 402 Brinell units, and a an hour.

. aoo Brinell units.

hardness of 720 Brinell units after being annealed at 700 C. for an hour.

2. An alloy 0!: cobalt 45%, tungsten 38%, iron 17% and carbon 0.1%, gave a hardness oi. 328 Brinell units after quenching from 1300 C. and a hardness of 554 Brinell units after annealing at 800 C. for an hour.

3. An alloy of: cobalt 56%, tungsten 26%, chromium 13%, iron 4.5%, vanadium 0.6% and carbon 0.06% gave a hardness of 315 Brinell units after quenching from 1200 C. and a hardness of 545 Brinell units after annealing at 800 C. for

I claim:-

1. The process which consists in forming an alloy comprising about 40 to cobalt, about 5 to 40% of tungsten and the balance constituting a substantial portion of the alloy consisting substantially or iron, said alloy containing carbon in amounts not exceeding 0.3%, subjecting {said alloy to a precipitation hardening by heating the alloy to a temperature between about that its hardness has been raised by at least 200 to xos'ma. 

